When bilateral and diffuse, it may be associated with ARF, fever, chills, flank pain, and hematuria.

When insidious in onset, may manifest as a concentrating defect or as progressive renal failure.

Typically affects adults (>60 years).

Bilateral in 70% of cases.

May be associated with any number of disease entities, but most common is diabetes mellitus; also: analgesic abuse, sickle cell disease.

Pathogenesis is ischemic, related to marginal blood supply of medulla (which explains prevalence in patients with underlying vascular disorders such as diabetics); also vasoconstriction due to prostaglandin inhibition by NSAID.